摘要 |
An aluminium oxide-coated tool has a coating comprising one or more group IVa, Va and VIa metal carbide, nitride and/or carbonitride layers (3), a compound layer (2) and one or more alpha aluminium oxide-based layers (1). The novelty is that (a) the compound layer (2) consists of an inner non-oxide compound layer (2-2) of group IVa, Va and VIa metal carbide, nitride and/or carbonitride and an outer oxide compound layer (2-1) of the oxide, oxycarbide, oxynitride and/or oxycarbonitride corresponding to the carbide, nitride and/or carbonitride of the non-oxide compound layer; and (b) the greatest intensity maximum in the X-ray diffraction pattern of the oxide layer (1) is the (110) crystal plane reflection. Also claimed is a process for producing the above coated tool, in which the non-oxide compound layer (2-2) and the oxide compound layer (2-1) are deposited at 950-1020 deg C, the deposition chamber being continuously supplied with the gas mixture for depositing the non-oxide compound layer and additionally 0.1-5 vol.% oxidising gas for deposition of the oxide compound layer. |